/****************************************************************************
* Copyright (c) 2008, j. montgomery, ATGi                                   *
* All rights reserved.                                                      *
*                                                                           *
* Redistribution and use in source and binary forms, with or without        *
* modification, are permitted provided that the following conditions        *
* are met:                                                                  *
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* - Redistributions of source code must retain the above copyright          *
*   notice, this list of conditions and the following disclaimer.           *
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* - Redistributions in binary form must reproduce the above                 *
*   copyright notice, this list of conditions and the following             *
*   disclaimer in the documentation and/or other materials provided         *
*   with the distribution.                                                  *
*                                                                           *
* - Neither the name of ATGi nor the names of its contributors may          *
*   be used to endorse or promote products derived from this software       *
*   without specific prior written permission.                              *
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS       *
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*****************************************************************************
*/
using System;
using System.IO;
using System.Text;

namespace DnSmtp.Message.Encoding
{
	/// <summary>
	/// Summary description for SevenBitEncodingStrategy.
	/// </summary>
	public class SevenBitEncodingStrategy : IEncodingStrategy
	{
		private static SevenBitEncodingStrategy _instance;
		
		public static SevenBitEncodingStrategy Instance
		{
			get
			{
				if(_instance == null) 
				{
					_instance = new SevenBitEncodingStrategy();
				}
				return _instance;
			}
		}

		protected SevenBitEncodingStrategy()
		{
		}

		#region IEncodingStrategy Members

		public string Name
		{
			get
			{
				return "7bit";
			}
		}

		public string Encode(object message)
		{
			UTF7Encoding utf7Encoder = new UTF7Encoding();
			string result = string.Empty;			

			if(message is Stream) 
			{
				byte[] bytes = new byte[((Stream)message).Length];
				((Stream)message).Read(bytes, 0, (int) ((Stream)message).Length);
				result = utf7Encoder.GetString(bytes);
			}
			else if(message is String) 
			{
				byte[] encodedBytes = utf7Encoder.GetBytes((string)message);
				result = utf7Encoder.GetString(encodedBytes);
			}
			else 
			{
				throw new NotImplementedException("Unable to encode message of type " + message.GetType().FullName);
			}

			return result;
		}
		#endregion
	}
}
